Answer:
blood; vessels; oxygen; circulatory
Explanation:
The first blank comes after the phrase "This organ is your heart, which pumps your ________ ". Our heart is the organ that works hard to pump oxygenated blood throughout our bodies so that we can live. So, that first blank should be "blood".
The second blank comes right after the first: "...your blood through blood ________ to all parts of your body". Blood travels through vessels; there are two kinds: arteries and veins. Here, the second blank should be "vessels".
The third blank is "_______ and food and removes waste". Here, it is talking about how certain beneficial substances are transported through the body and how harmful substances are removed. "Oxygen" should go here because all parts of our bodies need oxygen in order to be able to function properly.
The last blank, by elimination, must then be "circulatory". Putting it in, the sentence will read: "...your lungs bring in the oxygen that your circulatory system...". This makes sense because the circulatory system helps to transport oxygen through blood all over the body.
Hope this helps!
